Additive associative law: a+b+c=a+(b+c)
65438+ 0× number of copies per copy = total
Total copies/number of copies = number of copies
Total copies/number of copies = number of copies
2 1 multiple × multiple = multiple
Multiply1Multiply = Multiply
Multiply/Multiply = 1 Multiply
3 Speed × Time = Distance
Distance/speed = time
Distance/time = speed
4 unit price × quantity = total price
Total price/unit price = quantity
Total price ÷ quantity = unit price
5 Work efficiency × working hours = total workload.
Total amount of work ÷ work efficiency = working hours
Total workload ÷ working time = working efficiency
6 addend+addend = sum
And-one addend = another addend
7 minuend-minuend = difference
Negative difference = negative
Difference+Minus = Minus
8 factor × factor = product
Product ÷ One factor = another factor
Dividend = quotient
Dividend = divisor
Quotient × Divider = Divider
Calculation formula of mathematical graphics in primary schools
1 square
Perimeter area side length
Perimeter = side length ×4
C=4a
Area = side length × side length
S=a×a
2 cubic meters
Volume a: edge length
Surface area = side length × side length ×6
S table =a×a×6
Volume = side length × side length × side length
V=a×a×a
3 rectangle
Perimeter area side length
Circumference = (length+width) ×2
C=2(a+b)
Area = length × width
S=ab
4 cuboid
V: volume s: area a: length b: width h: height.
(1) Surface area (L× W+L× H+W× H) ×2
S=2(ab+ah+bh)
(2) Volume = length × width × height
V=abh
5 triangle
S area a bottom h height
Area = bottom × height ÷2
s=ah÷2
Height of triangle = area ×2÷ base.
Triangle base = area ×2÷ height
6 parallelogram
S area a bottom h height
Area = bottom × height
S = ah
7 trapezoid
Height of upper bottom b and lower bottom h in s area a
Area = (upper bottom+lower bottom) × height ÷2
s=(a+b)× h÷2
8 laps
Area c perimeter d= diameter r= radius
(1) circumference = diameter ×∏=2×∏× radius
C=∏d=2∏r
(2) area = radius × radius×∈
Cylinder 9
V: volume h: height s; Bottom area r: bottom radius c: bottom perimeter
(1) lateral area = bottom circumference × height.
(2) Surface area = lateral area+bottom area ×2
(3) Volume = bottom area × height
(4) Volume = lateral area ÷2× radius.
10 cone
V: volume h: height s; Bottom area r: bottom radius
Volume = bottom area × height ÷3
Total number ÷ Total number of copies = average value
Formula of sum and difference problem
(sum+difference) ÷ 2 = large number
(sum and difference) ÷ 2 = decimal
And folding problems.
Sum \ (multiple-1) = decimal
Decimal × multiple = large number
(or sum-decimal = large number)
Difference problem
Difference ÷ (multiple-1) = decimal
Decimal × multiple = large number
(or decimal+difference = large number)
Some may not.
The first unit multiplication
1, three digits times two digits, and the product is either four digits or five digits.
2. Calculation rules for multiplying three digits by two digits: first multiply the digits of two digits with each digit of three digits, and the product is aligned with the digits; Then multiply the number of two digits with each of the three digits, and the product is aligned with the ten digits; Finally, add the product twice.
3. Multiplication calculation method ending in 0: Now multiply the non-zero parts of the two multipliers, and then see how many zeros are at the end of the two multipliers, and add several zeros at the end of the product.
Unit 2 liters and milliliters
1, 1 l (L)= 1000 mL (ml, ml)
2. A cubic container whose length, width and height are 1 decimeter from the inside out is exactly 1 liter. 1 litre water weight 1 kg. A glass of water in life is about 250ml；; A pressure cooker can hold about 6 liters of water; A domestic pool can hold about 30 liters of water and a washbasin can hold about 10 liters of water. A bathtub has about 400 liters of water; The capacity of a thermos bottle is about 2 liters, a goldfish bowl is about 30 liters, a bottle of drinks is about 400 ml, a pot of water is about 5 liters, and a spoonful of water has 10 ml.
The total blood volume of a healthy adult is about 4000-5000 ml. Voluntary blood donors generally donate 200 ml of blood each time.
4. 1 ml is approximately equal to 20 drops of water.
The third unit triangle
1. Condition of enclosing triangle: the sum of the lengths of two short sides must be greater than the third side.
2. The vertical line segment from a vertex of a triangle to the opposite side is the height of the triangle, and this opposite side is the bottom of the triangle.
3. The triangle is stable (that is, the shape and size of the triangle will not change after the lengths of the three sides of the triangle are determined), and many objects in life take advantage of this feature. Such as: herringbone beam, cable-stayed bridge, bicycle frame.
4. A triangle with three acute angles is an acute triangle. (The sum of the two internal angles is greater than the third internal angle. )
5. A triangle with right angles is a right triangle. (The sum of the two internal angles is equal to the third internal angle. The sum of the two acute angles is 90 degrees. The two right-angled sides are the bottom and the height of each other. )
6. A triangle with an obtuse angle is an obtuse triangle. (The sum of the two internal angles is less than the third internal angle. )
7. Any triangle has at least two acute angles and three heights, and the sum of the internal angles of the triangle is 180 degrees. (All three heights of an acute triangle are within the triangle; A right triangle has two heights that fall on two right-angled sides; An obtuse triangle has two heights outside the triangle.
8. Divide a triangle into two right triangles to draw its height.
9. A triangle with two equal sides is an isosceles triangle. Two equal sides are called waist and the other side is called bottom. The angle between the two waists is called the top angle, and the angle between the buttocks and the waist is called the bottom angle. Its two bottom angles are also equal, and it is an axisymmetric figure with an axis of symmetry (just coincident with the height of the bottom). ) on three sides.
An equilateral triangle is an equilateral triangle with three equal sides and three equal angles.
Equal (each angle is 60, and all three angles of an equilateral triangle are 60. )
10, an isosceles triangle with a right angle is called an isosceles right triangle.
Its base angle is equal to 45 degrees and its top angle is equal to 90 degrees.
10, find one angle of the triangle =180-the sum of the other two angles.
1 1, top angle of isosceles triangle = 180- bottom angle ×2 = 180- bottom angle.
12, base angle of isosceles triangle =( 180- vertex angle) ÷2.
13, the maximum angle of a triangle is 60 degrees, and this triangle must be an equilateral triangle.
14, the sum of the inner angles of the polygon = 180× (n-2) {n is the number of sides}
Unit 4 Mixing Operation
1. In mixed operation: multiply first, then divide, then add and subtract. There are both parentheses and square brackets. You should count what is in brackets first, and then what is in brackets.
Unit 5 Parallelogram and Trapezoid
1, two groups of parallelograms whose opposite sides are parallel are called parallelograms, and their opposite sides are parallel and diagonal are equal. There can be two different heights from one vertex to the opposite.
Bottom and height must correspond. A parallelogram has countless heights.
2. Two identical triangular rulers can be used to make parallel lines.
quadrilateral
3. The parallelogram is easily deformed (unstable). Xu in life
Many objects take advantage of this feature. Such as: (electric retractable door, iron sliding door,
The elevator pulls the parallelogram into a rectangle with constant perimeter and variable area. Parallelogram is not an axisymmetric figure.
4. Only one set of quadrilaterals with parallel opposite sides is called trapezoid. flat
A set of rows with shorter opposite sides is called trapezoidal upper bottom, and the longer one is called trapezoidal upper bottom.
It is called the base of a trapezoid, and a group of non-parallel opposite sides is called a trapezoid.
Waist, the distance between two parallel lines is called the height of trapezoid.
(countless articles).
5. Two trapezoid with equal waist are called isosceles trapezoid. Its two base angles are equal, and it is an axisymmetric figure with an axis of symmetry. A right-angled trapezoid has only two right angles.
6. Two identical trapezoids can be combined into a parallelogram.
7. Square and rectangle belong to special parallelogram.
Unit 6 Looking for the Law
1, collocation law: the number of two things is multiplied. (for example, the matching of hat and clothes)
2. Finishing: (1) Mom and Dad and I arrange photos. There are several arrangements: 2×3.
(2) Five teams play football, one for every two teams. They should play a few rounds: 4+3+2+ 1.
Unit 7 Algorithm
1, multiplicative commutative law: a× b = b× a.
2. Multiplicative associative law: (a×b)×c=a×(b×c)
3. Multiplication distribution law: (a+b)×c=a×c+b×c (multiplying together equals multiplying separately).
4. Deduction: (a-b)×c=a×c-b×c
5. Typical example of simple operation:
102×35=( 100+2)×35 36× 10 1-36=36×( 10 1- 1)
35×98=35×( 100-2)=35× 100-35×2
Unit 8 Symmetry, Translation and Rotation
1. Draw the other half of the graph: (1) Find the symmetry axis (2) Find the corresponding point (3) Connect the graph.
2. A regular triangle (equilateral triangle) has three axes of symmetry, a regular quadrangle (square) has four axes of symmetry, a regular pentagon has five axes of symmetry, and a regular N deformation has n axes of symmetry.
3. Translation of graphics: first draw the translation direction, then translate the key points to the designated places, and finally connect them into graphics. I learned translation twice this semester. For example, I translate from upper left to lower right, first right and then right. )
4, the rotation of the graphics, first find a point, and then rotate the key edge to the specified place, (pay attention to the direction and angle) and then connect. (No matter translation or rotation, the basic graphics cannot be changed. )
Unit 9 Multiplication and Factor
1, 4×3= 12, or 12÷3=4. Then 12 is a multiple of 3 and 4, and 3 and 4 are factors of 12. (Multiplies and factors exist mutually. It cannot be said that 12 is a multiple or 3 is a factor. We can only say who is a multiple of who and who is a factor of who. )
2. The minimum factor of a number is 1, and the maximum factor is itself. The number of factors of a number is limited. For example, the factors of 18 are: 1, 2,3,6,9, 18.
The minimum multiple of a number is itself, and there is no maximum multiple. The multiple of a number is infinite. For example, the multiple of 18 is: 18, 36, 54, 72, 90 ... (ellipsis is very important).
The biggest factor of a number is equal to the smallest multiple of this number (both are themselves).
5. Numbers that are multiples of 2 are called even numbers. (Units are numbers 0, 2, 4, 6 and 8)
6. Numbers that are not multiples of 2 are called odd numbers. (The unit number is 1, 3, 5, 7, 9)
7. Numbers with units of 2, 4, 6, 8 and 0 are multiples of 2, and numbers with units of 0 or 5 are multiples of 5.
8. It is both a multiple of 2 and a multiple of 5, and each bit must be 0. (For example: 10, 20, 30, 40 ...)
9. The sum of digits of a number is a multiple of 3, and this number is a multiple of 3. (For example, the sum of the digits of 453 is 4+3+5= 12. Because 12 is a multiple of 3, 453 is also a multiple of 3. )
10, a number with only 1 and its own two factors is called a prime number. (or prime numbers) such as: 2, 3, 5, 7, 1 1 3, 17, 19...2 is the only even number in the prime number. So it is wrong to say that all prime numbers are odd numbers. )
1 1, a number with other factors besides 1, is itself called a composite number. Such as: 4, 6, 8, 9, 10 ...
12 and 1 are neither prime nor composite numbers, because the factor of 1 is only 1: 1.
13, Goldbach conjecture: Any even number greater than 2 is the sum of two prime numbers. 20=3+ 17、40= 1 1+2、8=3+5、 10=3+7、 12=5+7、 14=3+ 1 1=7+7、30=23+7= 13+ 17
Prime numbers within 14 and 100: 2, 3, 5, 7, 1 1 3, 17, 19, 23, 29.
15, three consecutive natural numbers (3, 4, 5), three consecutive odd numbers (3, 5, 7) and the sum of three consecutive even numbers (4, 6, 8) are all multiples of 3.
Unit 10 Exploring Laws with Calculator
The changing law of the product of 1 sum;
(1) One factor is reduced by several times, and the other factor is expanded by the same multiple, and the product remains unchanged.
(2) If one factor shrinks (or expands several times) and the other factor remains unchanged, the product will also shrink (or expand) several times.
2, the change law of quotient:
(1) The divider and divisor are expanded (or reduced) by the same multiple at the same time, and the quotient remains unchanged except 0. (The rest will change)
(2) The divisor is expanded (or reduced) several times, and the quotient is also expanded (or reduced) several times under the condition that the divisor is unchanged.
(3) The dividend is constant, the divisor is reduced several times (except 0), but the quotient is expanded several times.
Unit 12 Statistics
1, broken-line statistical chart can not only see the numbers, but also clearly see the increase and decrease of the numbers. The production steps of broken-line statistical chart: ① fixed point ② writing data ③ connecting line ④ writing date.
Unit 13 uses letters to represent numbers.
1, using letters to represent the basic law of numbers:
If the side length of a square is represented by a, the perimeter is represented by c, and the area is represented by s, then: the perimeter of the square: C=a×4 square area: s = a× a.
A×4 or 4×a can generally be written as 4? A or 4a; A×a can be written as a? A can also be written as a2, which is pronounced as "the square of A". If a is multiplied by 1, it can be written directly as a.
Attachment: Common quantitative relations
Area of a square = side length × side length (S=a×a=a2)
Circumference of a square = side length ×4 (C=a×4=4a)
Area of rectangle = length× width (S=a×b=ab)
The circumference of a rectangle = (length+width) × 2c = (a+b) × 2.
Total price = unit price × quantity unit price = total price/quantity = total price/unit price.
Distance = speed × time speed = distance/time = distance/speed
Federation of trade unions = work efficiency × time efficiency = time of Federation of trade unions = time of Federation of trade unions.
Room area = area of each floor tile × number of tiles.
Number of blocks = room area ÷ area of each block
Meeting distance = (speed A+ speed B) × meeting time = speed A × time+speed B × time.
Distance = (speed A- speed B) × time = speed A × time b
Mathematics review outline for the next four years
The main content of the field is more important than the difficulty.
Digital and algebraic multiplication three-digit multiplication two-digit pen calculation
Three-step calculation method to solve practical problems; written calculation with 0 in the middle of three digits. Three digits multiplied by two digits, the product is either four digits or five digits.
Multiplication method with zeros at the end: multiply the non-zero parts of two multipliers first, then see how many zeros are at the end of the two multipliers, and add a few zeros at the end of the product.
The three steps of mixed operation calculate the operation order of mixed operation, in parentheses. Clarify the operation sequence and improve the calculation accuracy. Multiplication and division before addition and subtraction; There are both brackets and brackets. Count those in brackets first, then those in brackets.
Arithmetic applies multiplication and distribution laws to perform simple operations, such as multiplication, commutative law, associative law and distribution law. 1, multiplicative commutative law: a× b = b× a.
2. Multiplicative associative law: (a×b)×c=a×(b×c)
3. Multiplication distribution law: (a+b)×c=a×c+b×c (multiplying together equals multiplying separately).
4. Expand: (a-b) × c = a× c-b× c
5. Typical example of simple operation:102× 35 = (100+2 )× 35.
36× 10 1-36=36×( 10 1- 1) 35×98=35×( 100-2)=35× 100-35×2
Use a calculator
Explore the changing law of regular products
The invariant law of quotient, the simple method of calculating dividend and division with 0 at the end of divisor, and its application in calculating and solving practical problems. The changing law of the product of 1 sum;
One factor is reduced (or expanded several times), while the other factor is unchanged, and the product is also reduced (or expanded) by the same multiple.
2, the change law of quotient:
Dividend and divisor are expanded (or reduced) by the same multiple at the same time, and the quotient remains unchanged except 0. (The rest will change)
multiple
Find all multiples of a natural number within 10 (within 100) and all factors of a natural number within 100.
Even and odd numbers, the characteristics of prime numbers and composite numbers, and the characteristics of multiples of 2, 5 and 3 are comprehensively judged on the basis of grasping the meaning to understand the characteristics of each kind of natural numbers. 1, 4×3= 12, or 12÷3=4. Then 12 is a multiple of 3 and 4, and 3 and 4 are factors of 12. (Multiplies and factors exist mutually. It cannot be said that 12 is a multiple or 3 is a factor. We can only say who is a multiple of who and who is a factor of who. )
2. The minimum factor of a number is 1, and the maximum factor is itself. The number of factors of a number is limited.
The minimum multiple of a number is itself, and there is no maximum multiple. The multiple of a number is infinite.
The biggest factor of a number is equal to the smallest multiple of this number (both are themselves).
5. Numbers that are multiples of 2 are called even numbers. (Units are numbers 0, 2, 4, 6 and 8)
6. Numbers that are not multiples of 2 are called odd numbers. (The unit number is 1, 3, 5, 7, 9)
7. Numbers with units of 2, 4, 6, 8 and 0 are multiples of 2, and numbers with units of 0 or 5 are multiples of 5.
8. It is both a multiple of 2 and a multiple of 5, and each bit must be 0.
9. The sum of digits of a number is a multiple of 3, and this number is a multiple of 3. (For example, the sum of the digits of 453 is 4+3+5= 12. Because 12 is a multiple of 3, 453 is also a multiple of 3. )
10, a number with only 1 and its own two factors is called a prime number (or prime number). Such as: 2, 3, 5, 7,1,13, 17, 19, 23, 29, 3 1, 37, 4/kloc. ...
2 is the only even number in prime numbers. (So "all prime numbers are odd numbers" is wrong. )
1 1, a number with other factors besides 1, is itself called a composite number.
12 and 1 are neither prime nor composite numbers, because the factor of 1 is only 1: 1.
Prime numbers within 13 and 100: 2, 3, 5, 7, 1 1 3, 17, 19, 23, 29.
14, three consecutive natural numbers (3, 4, 5), three consecutive odd numbers (3, 5, 7) and the sum of three consecutive even numbers (4, 6, 8) are all multiples of 3.
Find the law and further understand the law of simple collocation and simple arrangement in life. Arrange or arrange several things in an orderly manner. Solve some simple practical problems with laws. 1, collocation law: the number of two things is multiplied. (for example, the matching of hat and clothes)
2. Finishing: (1) Mom and Dad and I arrange photos. There are several arrangements: 2×3.
(2) Five teams play football, one for every two teams. They should play a few rounds: 4+3+2+ 1.
Use letters
Using formulas containing letters to represent numbers is a simple quantity, quantitative relationship and formula. Find the value of the formula containing letters and simplify the formula of "ax+bx". Use letters to indicate the quantitative relationship in a specific situation. 1, using letters to represent the basic law of numbers:
If the side length of a square is represented by a, the perimeter is represented by c, and the area is represented by s, then: the perimeter of the square: C=a×4 square area: s = a× a.
A×4 or 4×a can usually be written as 4 a or 4 a; A×a can be written as a or a2, and read as "the square of a". If a is multiplied by 1, it can be written directly as a.
2. Use letters to express the quantitative relationship: Xiaoling went to the store and bought 1 pen and 4 notebooks, each pen is 7 yuan, and each notebook is one yuan. She paid (7+4A) yuan.
3. Use numbers instead of letters to find the value of formulas containing letters. 4. Simplify the formula containing letters.
solve problems
Strategy of
Use the strategy of drawing list to solve the practical problems about area and travel, and use drawing to solve the problem of area increase and decrease.
Draw the schematic diagram correctly
Reasonable list
Commonly used quantitative relations:
Area of a square = side length × side length (S=a×a=a2)
Circumference of a square = side length ×4 (C=a×4=4a)
Area of rectangle = length× width (S=a×b=ab)
The circumference of a rectangle = (length+width) × 2 (c = (a+b) × 2)
Total price = unit price × quantity unit price = total price/quantity = total price/unit price.
Distance = speed × time speed = distance/time = distance/speed
Federation of trade unions = work efficiency × time efficiency = time of Federation of trade unions = time of Federation of trade unions.
Room area = area of each floor tile × number of tiles.
Number of tiles = room area ÷ area of each tile
Meeting distance = (speed A+ speed B) × meeting time = speed A × time+speed B × time.
Distance = (speed A- speed B) × time = speed A × time-speed B × time.
The classification of spatial and graphic triangles, the sum of internal angles, the degree of the third triangle, and the application of correctly measuring and drawing that the sum of two sides of the triangle is greater than the third side. 1. Condition of enclosing triangle: the sum of the lengths of two short sides must be greater than the third side.
2. The vertical line segment from a vertex of a triangle to the opposite side is the height of the triangle, and this opposite side is the bottom of the triangle.
3. Classification of triangles: (by edge)
A triangle with three acute angles is an acute triangle. (The sum of the two internal angles is greater than the third internal angle. )
A triangle with right angles is a right triangle. (The sum of the two internal angles is equal to the third internal angle. The sum of the two acute angles is 90 degrees. The two right-angled sides are the bottom and the height of each other. )
A triangle with an obtuse angle is an obtuse triangle. (The sum of the two internal angles is less than the third internal angle. )
A triangle with equal sides is an isosceles triangle. Two equal sides are called waist and the other side is called bottom. The angle between the two waists is called the top angle, and the angle between the buttocks and the waist is called the bottom angle. Its two base angles are also equal, and it is an axisymmetric figure with an axis of symmetry. )
A triangle with three equal sides is an equilateral triangle, all three sides are equal and all three angles are equal (each angle is 60, and all three angles of an equilateral triangle are 60). )
4. Any triangle has at least two acute angles and three heights, and the sum of the internal angles of the triangle is 180 degrees.
5. Divide a triangle into two right triangles to draw its height.
6. An isosceles triangle with a right angle is called an isosceles right triangle. Its base angle is equal to 45 degrees and its top angle is equal to 90 degrees.
7. Find the sum of one angle of a triangle = 180- the other two angles.
8. The top angle of an isosceles triangle = 180- bottom angle ×2 = 180- bottom angle-bottom angle.
9. The base angle of an isosceles triangle =( 180- vertex angle) ÷2
10, the maximum angle of a triangle is 60 degrees, and this triangle must be an equilateral triangle.
1 1, the sum of the interior angles of the polygon = 180× (n-2) {n is the number of sides}
The characteristics of parallelogram and trapezoid, correctly measure and draw the height of parallelogram and trapezoid. Draw the height according to the base of parallelogram and trapezoid. Conversion between graphics.
1, two groups of parallelograms whose opposite sides are parallel are called parallelograms, and their opposite sides are parallel and diagonal are equal. There can be two different heights from one vertex to the opposite. Bottom and height must correspond. A parallelogram has countless heights.
2. Two identical triangular rulers can be used to form a parallelogram.
3. The parallelogram is easily deformed (unstable). Many objects in life take advantage of this feature. Such as: (electric retractable doors, iron sliding doors, elevators) draw a parallelogram into a rectangle, with the perimeter unchanged and the area changed. Parallelogram is not an axisymmetric figure.
4. Only one set of quadrilaterals with parallel opposite sides is called trapezoid. flat
A set of rows with shorter opposite sides is called trapezoidal upper bottom, and the longer one is called trapezoidal upper bottom.
It is called the base of a trapezoid, and a group of non-parallel opposite sides is called a trapezoid.
Waist, the distance between two parallel lines is called the height of trapezoid.
(countless articles).
5. Two trapezoid with equal waist are called isosceles trapezoid. Its two base angles are equal, and it is an axisymmetric figure with an axis of symmetry. A right-angled trapezoid has only two right angles.
6. Two identical trapezoids can be combined into a parallelogram.
7. Square and rectangle belong to special parallelogram.
Symmetry and translation
And draw the symmetry axis of a simple axisymmetric figure. Draw the other half according to the symmetry axis
Translate simple graphics twice in succession on grid paper. Rotate the simple figure by 90 degrees to draw the figure 1 after the simple figure is rotated by 90 degrees counterclockwise and clockwise, and draw the other half of the figure: (1) Find the symmetry axis (2) Find the corresponding point (3) Connect the figure.
2. A regular triangle (equilateral triangle) has three axes of symmetry, a regular quadrangle (square) has four axes of symmetry, a regular pentagon has five axes of symmetry, and a regular N deformation has n axes of symmetry.
3. Translation of graphics: first draw the translation direction, then translate the key points to the designated places, and finally connect them into graphics. I learned translation twice this semester. For example, I translate from upper left to lower right, first right and then right. )
4, the rotation of the graphics, first find a point, and then rotate the key edge to the specified place, (pay attention to the direction and angle) and then connect. (No matter translation or rotation, the basic graphics cannot be changed. )
L and ml. The forward speed between l and ml. The application of liters and milliliters in life. The application of liters and milliliters in life 1, 1 liter (L)= 1000 milliliters (mL, ml).
2. A cubic container whose length, width and height are 1 decimeter from the inside out is exactly 1 liter. 1 litre water weight 1 kg. A glass of water in life is about 250ml；; A pressure cooker can hold about 6 liters of water; A domestic pool can hold about 30 liters of water and a washbasin can hold about 10 liters of water. A bathtub has about 400 liters of water; The capacity of a thermos bottle is about 2 liters, a goldfish bowl is about 30 liters, a bottle of drinks is about 400 ml, a pot of water is about 5 liters, and a spoonful of water has 10 ml.
The total blood volume of a healthy adult is about 4000-5000 ml. Voluntary blood donors generally donate 200 ml of blood each time.
4. 1 ml is approximately equal to 20 drops of water.
Statistical statistics draw a broken-line statistical chart and analyze the data of the broken-line statistical chart. Choose a bar chart or line chart according to the data characteristics and actual needs. Analyze the data of broken line statistical chart. The broken-line statistical chart can not only see the quantity, but also clearly see the increase and decrease of the quantity. The production steps of broken-line statistical chart: ① fixed point ② writing data ③ connecting line ④ writing date.
Respondent: 6 1084773400 | Level 1 | 201-6-1917: 38.
I. Operation sequence:
In the formula without brackets, if there is only addition and subtraction or only multiplication and division, there is sequential calculation. There are addition, subtraction and multiplication and division in the formula without brackets, so multiply and divide first, then add and subtract. When there are parentheses in the formula, count the parentheses first. Addition, subtraction, multiplication and division are called four operations. Add 0 to a number to get the original number. Any number multiplied by 0 gets 00, which cannot be divided by all. 0 divided by a nonzero number equals 0. Dividing 0 by 0 does not get a fixed quotient. Divide 5 by 0 to get no quotient.
Second, the position and direction
1. Determine or draw a specific point of an object according to the direction and distance. (Drawing and measuring scale and angle)
2. Relativity between positions. The relationship between two objects will be described. (Determination of observation points)
B is 30 degrees 2000 meters east of A;
A is 30 degrees 200 meters southwest of B.
3. Draw a simple road map.
Third, the operation method and simple operation:
1. law of addition:
Additive commutative law: When two numbers are added, the position of the addend is reversed and the sum remains the same. a+b=b+a
Law of addition and association: when three numbers are added, the first two numbers can be added first and then the third number can be added; Or add the last two numbers and the first number together, and the sum remains the same. The two laws of (a+b)+c=a+(b+c) addition are often used together. For example:165+93+35 = 93+(165+35) What is the basis?
.2. The nature of continuous reduction: one number minus two numbers equals the sum of this number minus those two numbers. a-b-c=a-(b+c)
3, the law of multiplication:
Multiplication and exchange law: when two numbers are multiplied, the position of the exchange factor remains unchanged. bXa=aXb
Multiplication and association law: when three numbers are multiplied, you can multiply the first two numbers and then the third number, or you can multiply the last two numbers and then the first number, and the product remains unchanged. The two laws of (axb)xc=ax(bxc) multiplication are often used together. Such as: (axb)xc=ax(bxc). Such as: 125
Multiplication distribution rate: the sum of two numbers multiplied by one number. You can multiply these two numbers by these two numbers respectively, and then add up the products. (a+b)xc=axc+bxc
4. The nature of continuous division: one number divided by two numbers equals the product of these two numbers. A divided by B divided by c=a divided by {b multiplied by c}
A+b = b+a {a+b}+c = a+{b+c}165+93+35 = 93+{165+35} {a+b} xc = axc+bxc. The denominator is/kloc-.
The unit of decimal is _ 10%. One thousandth.
The ratio of every two adjacent counting units is+integer reading. Decimals are read out in turn. Write decimals every 1 integer to remove the last decimals.
Decimals are expanded ten times, some are shifted one place to the right, expanded 100 times, and shifted two places to the right one thousand times. . .
Decimal shift left by one place+once, two places, one hundred times, three places and one thousand times. ...
Reserved-decimal places are accurate to+decimal places, 2 decimal places are accurate to 1%, and 3 decimal places are accurate to 1/1000.
A figure surrounded by three sides is called a triangle.
1 angles of a triangle form a straight line with its opposite side. This straight line is called the height of the triangle, and its opposite side is called the bottom of the triangle.
The feature is stable, and any two sides are greater than three sides.
Classification of angles; The size is divided into acute angle, right angle and obtuse angle, and the length is divided into three unequal isosceles triangles, which are always equal to 180 degrees. Two triangles can spell a parallelogram.
The calculation of decimal point alignment is called decimal addition and subtraction. Number of intervals between points drawn by lines in data = total length divided by interval length.
The number of trees planted at both ends is equal to the interval+1. Only the number of trees planted at one end is equal to the interval.
No tree = interval-
Number of closed trees = interval